J. Christie
A5086569699- Nuclear physics research studies
- Nuclear Physics and Applications
- Astronomical and nuclear sciences
- Neutrino Physics Research
- Crystallography and molecular interactions
- Atomic and Molecular Physics
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Quantum Chromodynamics and Particle Interactions
- Superconductivity in MgB2 and Alloys
- Medical Imaging Techniques and Applications
- Advanced Neural Network Applications
- Particle physics theoretical and experimental studies
- Superconducting Materials and Applications
- Atomic and Subatomic Physics Research
- Particle accelerators and beam dynamics
- Rare-earth and actinide compounds
- Scientific Research and Discoveries
- Radiation Detection and Scintillator Technologies
- Advanced NMR Techniques and Applications
- Electron and X-Ray Spectroscopy Techniques
- Advanced X-ray Imaging Techniques
- X-ray Spectroscopy and Fluorescence Analysis
- Geophysics and Gravity Measurements
University of Tennessee at Knoxville
2022-2024
Excited-state spectroscopy from the first Facility for Rare Isotope Beams (FRIB) experiment is reported. A 24(2)-$\mu$s isomer was observed with FRIB Decay Station initiator (FDSi) through a cascade of 224- and 401-keV $\gamma$ rays in coincidence $^{32}\textrm{Na}$ nuclei. This only known microsecond ($1{\text{ }\mu\text{s}}\leq T_{1/2} < 1\text{ ms}$) region. nucleus at heart $N=20$ island shape inversion crossroads spherical shell-model, deformed ab initio theories. It can be represented...
In the pursuit of identifying rare two-particle events within GADGET II Time Projection Chamber (TPC), this paper presents a comprehensive approach for leveraging Convolutional Neural Networks (CNNs) and various data processing methods. To address inherent complexities 3D TPC track reconstructions, is expressed in 2D projections 1D quantities. This capitalizes on diverse modalities TPC, allowing efficient representation distinct features events, with no loss topology uniqueness....
New half-lives for exotic isotopes approaching the neutron drip-line in vicinity of N∼28 Z=12-15 were measured at Facility Rare Isotope Beams (FRIB) with FRIB decay station initiator. The first experimental results are compared to latest quasiparticle random phase approximation and shell-model calculations. Overall, consistent available theoretical descriptions suggest a well-developed region deformation below ^{48}Ca N=28 isotones. erosion Z=14 subshell closure Si is experimentally...
The first complete measurement of the β-decay strength distribution Cl281745 was performed at Facility for Rare Isotope Beams (FRIB) with FRIB Decay Station Initiator during second experiment. involved detection neutrons and γ rays in two focal planes a single experiment time. This enabled an analytical consistency extracting over large range excitation energies, including neutron unbound states. We observe rapid increase above separation energy Ar271845. interpreted to be caused by...
We observed a new isomeric $\ensuremath{\gamma}$ transition at 168 keV in $^{36}\mathrm{Mg}$, with half-life of ${T}_{1/2}=90{(}_{\ensuremath{-}50}^{+410})$ ns. propose that the deexcites ${0}^{+}$ state 833 and populates previously known first ${2}^{+}$ state. The existence this isomer is consistent predictions large-scale shell-model calculations $^{36}\mathrm{Mg}$ using sdpf-u-mix interaction. excitation energy second caused by small separation between two prolate-deformed configurations...
Single-step Coulomb excitation of 46,48,49,50Ti is presented. A complete set E2 matrix elements for the quintuplet states in 49Ti, centred on 2+ core excitation, was measured first time. total nine are reported, four which were previously unknown. 2249Ti27 shows a 20% quenching electric quadrupole transition strength as compared to its semi-magic 2250Ti28 neighbour. This quenching, while empirically unprecedented, can be explained with remarkably simple two-state mixing model, also...
The level structure of $^{36}\mathrm{Al}$ has been studied via $\ensuremath{\beta}$ decay $^{36}\mathrm{Mg}$ at the Facility for Rare Isotope Beams (FRIB) and National Superconducting Cyclotron Laboratory (NSCL). A long-lived isomer in was identified which decays by to an excited state $^{36}\mathrm{Si}$. ground isomeric were found populate different energy levels results from two data sets present work complement each other. Configuration interaction calculations performed with FSU...
Single-step Coulomb excitation of $^{46,48,49,50}$Ti is presented. A complete set $E2$ matrix elements for the quintuplet states in $^{49}$Ti, centered on $2^+$ core excitation, was measured first time. total nine are reported, four which were previously unknown. $^{49}_{22}$Ti$_{27}$ shows a $20\%$ quenching electric quadrupole transition strength as compared to its semi-magic $^{50}_{22}$Ti$_{28}$ neighbour. This quenching, while empirically unprecedented, can be explained with remarkably...
We measured the $\beta$-delayed neutron emission from $^{25}$F for first time at Facility Rare Isotope Beams (FRIB). Using combined and $\gamma$-ray detector systems of FRIB Decay Station Initiator (FDSi), we observed $\beta$-decay transitions populating unbound states between 4.2 8 MeV in $^{25}$Ne. The experimental results led to revision half-life neutron-emission probability $^{25}$F. strength distribution extracted data agrees with shell-model predictions using USDB SDPF-M effective...
We observed a new isomeric gamma transition at 168 keV in $^{36}$Mg, with half-life of T$_{1/2}$=[130-500]$(\pm40)(^{+800}_{-20})_{sys}$ ns. propose that the de-excites 0$^+$ state and populates previously known first 2$^+$ state. The existence this isomer is consistent predictions large-scale shell model calculations $^{36}$Mg using sdpf-u-mix interaction. excitation energy second caused by small separation between two prolate-deformed configurations where intruder configuration corresponds...
Excited-state spectroscopy from the first Facility for Rare Isotope Beams (FRIB) experiment is reported. A 24(2)-$μ$s isomer was observed with FRIB Decay Station initiator (FDSi) through a cascade of 224- and 401-keV $γ$ rays in coincidence $^{32}\textrm{Na}$ nuclei. This only known microsecond ($1{\text{ }μ\text{s}}\leq T_{1/2} < 1\text{ ms}$) region. nucleus at heart $N=20$ island shape inversion crossroads spherical shell-model, deformed ab initio theories. It can be represented as...